Work out fire load calculation instantly with clear inputs, formula shown and shareable results.
Fire load density is the effective heat content of the combustibles divided by compartment floor area, with a combustion efficiency factor because not all material burns completely. Dividing by about 20 MJ/m² per minute of standard fire exposure gives an equivalent fire duration, which is what fire resistance periods are calibrated against.
Fire load density
MJ/m² = mass x calorific value x combustion efficiency / floor area
Equivalent duration
Minutes = fire load density / 20
Preliminary estimate only. Fire load assessment and required fire resistance must be determined by a qualified fire engineer to the applicable code.
MJ/m² = mass x calorific value x combustion efficiency / floor area. Fire load density is the effective heat content of the combustibles divided by compartment floor area, with a combustion efficiency factor because not all material burns completely.
Strongly. The same fire load burns slowly in a poorly ventilated compartment and fiercely in a well ventilated one, which is why modern fire engineering uses ventilation-controlled parametric curves rather than fire load alone.
This calculator takes 4 inputs: Mass of combustible material, Average calorific value, Compartment floor area, Combustion efficiency. The pre-filled defaults are a realistic worked example — replace them with your own site or project figures.